1. Field of the Disclosure
This invention relates generally to the field of central vacuum systems and more particularly to inlet valves on central vacuum systems, of the type which receives a hose cuff of a central vacuum hose to connect the vacuum hose to a source of suction. Most particularly this invention relates to those types of inlet valves that include a current carrying electrical receptacle to connect a powered accessory (e.g., beater bar motor), carried for example at the end of a vacuum wand at a far end of the hose to a source of electrical power through said inlet valve.
2. Brief Discussion of Related Art
Current carrying inlet valves are known in central vacuum cleaner systems. Often they include a backing or mounting element, sometimes referred to as a mounting plate, secured to a stud or the like within a wall and an inlet valve, which is in turn secured to the mounting element. The inlet valve and the mounting element combine to form an inlet into vacuum piping running through the walls. The inlet valve usually is provided with a hinged cover which closes and seals a central vacuum opening when the valve is not in use. The opening in turn is connected to central vacuum piping network through which the suction is provided.
Typically low voltage electrical contacts are provided within the central vacuum opening and a conductive sleeve or a split ring configuration is provided on an insertion hose cuff of an associated central vacuum hose so that when the hose cuff is inserted into the opening a circuit is completed energizing a remote central vacuum motor to create the desired suction in the piping network. In this way, airflow is passed through the hose from a free end, for example through an attached accessory where it can be used to draw dirt, debris and the like into the hose, then through the valve and into and through the piping network until it is deposited in a debris collecting receptacle. The receptacle is associated with the vacuum source and is detachable to permit it to be periodically emptied.
A current carrying inlet valve assembly is one which also includes a high voltage (usually household current) electrical connection in the inlet valve assembly to complete a circuit to power an accessory such as a beater bar or the like at the free end of the hose or wand. In one form of prior current carrying inlet valve assembly as taught in U.S. Pat. No. 4,758,170 (Hayden), the inlet includes a female receptacle permanently mounted to the back of the valve, but accessible from the front of the valve through an opening in the valve so that a male pronged plug formed as part of the insertion hose cuff on the central vacuum hose can electrically mate with the female receptacle when the hose cuff is connected to the source of suction through the inlet valve assembly. In other words the electrical and vacuum connections are made at the same time through adjacent connections.
However, this prior design requires connecting the standard household wiring to the back of the female plug receptacle, behind the inlet valve assembly. Such a connection is an open electrical connection creating the need, according to standard building codes, for an electrical box located behind the inlet valve within which to enclose the electrical connection made between the open or bare wires. This type of connection requires the usual wire nuts and twisted wire combination of a conventional electrical wiring connection. The ground wire in a conventional electrical installation is either connected to the metal box or to the plug or receptacle directly. Because of the space limitations imposed by the presence of the central vacuum piping, and the receptacle position required to mate with the hose cuff, there is little room for the code required electrical box. As a result the prior art teaches using a box which is molded in a curved shape to fit over the vacuum piping or fitting. This makes it awkward for an electrician to complete the wiring connection within the small sized awkwardly shaped box. Further the need for a separate specially molded electrical box adds to the number of parts required in the central vacuum valve assembly and so adds to the expense of the overall valve system and the installation thereof.
In an attempt to address these problems a further design was developed as taught in U.S. Pat. Nos. 5,886,299, 5,578,795 and 5,448,827 in which a pig tail lead (molded plug with wires) was fabricated which was made field mountable into the inlet valve during installation. Mounting means are provided on the front of the flexible plastic plug to allow it to be deformed and rotated into place behind the inlet valve, where it is accessible to a male plug built into a hose cuff of a central vacuum hose. The electrical wire is factory molded into the plug, eliminating any open or bare wire electrical connection at the rear of the plug and eliminating therefore the need for an electrical box directly behind the inlet valve assembly. All that is required to complete an installation is to feed the pig tail wire back to an existing nearby electrical box to complete the bare wire electrical connections in the box in conformance to electrical code requirements. Although this works well for installations where the existing electrical box is close to where the central vacuum inlet valve is installed, it requires a preset amount of electrical wire to be provided as the pig tail lead for every molded plug. If this wire is too long, then it is cut off and wasted. If it is too short, it won't reach and thus will require the installer to mount a further electrical box within reach, thereby increasing the installation time and cost. Therefore while solving some of the problems of the previous invention, by simplifying the valve assembly and installation procedures, it creates some other additional issues which need to be addressed.
Other examples of prior art devices include: U.S. Pat. No. 4,790,771; U.S. Pat. No. 5,004,428; U.S. Pat. No. 5,127,153; U.S. Pat. No. 5,190,469; U.S. Pat. No. 5,785,551; U.S. Pat. No. 6,682,363; U.S. Pat. No. 7,637,760; and United States Patent Application Publication No. US2011/0100485 A1.
What is desired, is an improved design that overcomes the disadvantages of the prior art.